Engines, including diesel engines, gasoline engines, natural gas engines, and other engines known in the art, may exhaust a complex mixture of air pollutants. The air pollutants may be composed of both solid material, such as, for example, particulate matter, and gaseous material, which may include, for example, oxides of nitrogen, such as NO2 and NO3 (commonly referred to collectively as “NOx”).
Due to increased environmental concerns, exhaust emission standards have become more stringent. The amount of particulate matter and gaseous pollutants emitted from an engine may be regulated depending on the type, size, and/or class of engine. In order to meet these emissions standards, engine manufacturers have pursued improvements in several different engine technologies, such as fuel injection, engine management, and aftertreatment to name a few.
For example, it has been recognized that a more homogeneous mixture of fuel and air in a combustion chamber can lead to more efficient combustion, resulting in reduced engine emissions. U.S. Pat. No. 4,052,004 (“the '004 patent”) issued to Martin et al. discloses a vibratory atomizer for atomizing a fuel delivered to an engine. The atomizer includes a piezoelectric crystal that serves to vibrate a nozzle and body portion of the device so that fuel leaves through a single outlet by way of the nozzle in a finely atomized form. While the atomizer of the '004 patent does deliver a finely atomized fuel to an engine, the shape of the nozzle of the '004 patent tapers down toward its outlet and thus serves to consolidate the atomized fuel rather than disburse the fuel toward a more homogeneous mixture with the air. Further, the '004 patent does not disclose using the atomizer in connection with engine aftertreatment.
The present disclosure is directed at solving one or more of the deficiencies discussed above.